A Supreme Court appeal on surrogacy rights has heard that Irish law provides for a declaration of parenthood based on hereditary characteristics.

The seven judges are today hearing from lawyers acting for the genetic parents of twins born to a surrogate mother.

The High Court last year gave a landmark ruling that the genetic mother is the legal mother of the twins and that her name should appear on their birth certificates.

The State is challenging the decision as 'radically wrong' and has argued that in law it is the surrogate who is the children's mother because she gave birth to them.

Lawyers for the genetic couple claim their case is supported by the 1987 Status of Children Act, which provides for a declaration of parenthood based on the assistance of blood tests.

Gerard Durcan SC, for the couple, says blood tests have given way to the certainty of DNA testing, and what is clear is that 'for better or worse' the legislature has set up a method of determining parenthood based on inheritable characteristics.

He claims that unlike England, where a suite of measures were brought in to address parenthood in light of scientific advances such as IVF, the law here has so far failed to evolve to meet these changes.

The appeal is due to finish tomorrow.